X-Axis Stuttering
I purchased a MK3S kit in early Feb. Finished the build in early Apr. Printed one print using Solidworks and Slic3r with no problems. Didn't use the printer for a few weeks and then had a problem. I turned the printer on and upgraded Slic3r and then tried to do my print. The x-axis moved about 3mm back and forth from where it was while the other axis moved fine. I then updated the printer to the latest release thinking that might be the issue. This did not fix the problem. I then swapped the x and y axis to manually move them and see if the problem was swapped to the y axis or it stayed with the x axis. The problem did not change. Removed the belt to see if the motor was being affected by the belt tension. This did not change the stuttering.
The self test fails on the x axis and says "Please check axis length, axis x". I checked the Belt Status and it reads x- 21 and y-273. The belt however is loose. To make sure the belt it not too tight I removed it an re-ran the self test. It now reads 60 on the x axis motor. The pulley is spaced away from the motor, so that is not creating high drag. I am able to turn the motor by hand and it does not seem to turn any harder than the others with the belt removed.
Looking for thoughts on what to do next.
Thank you
RE: X-Axis Stuttering
Commonly two issues:
1) Gear is not properly attached to motor shaft. 2) Sticky bearings.
If sticky bearings, you can feel the axis hanging up when you manually press the extruder or bed stop to stop. There will be a "sticky" spot you can feel. It usually isn't a single spot: rather, the position of the sticky changes since the bearings rarely align at the same place. But you can feel the stiction as you move the axis. Grease helps. Even a drop or two of motor oil can work as a test.
For gears that are shifting - here's the proper way to install dual set screw parts.
Flat First: Drive gears must be tightened flat-first.
1) Start with both set screws fully loosened so the pulley is free to spin on the motor shaft.
2) Align one set screw dead center with the flat on the motor shaft, slowly tighten the screw until it fully contacts the flat surface.
3) Torque the flat set screw to spec.
4) Now tighten the jam set screw, and torque it to spec.
Once tightened, never touch the flat set screw unless the jam screw is first fully loosened.
Why Flat First? Set screws have flat ends. If you tighten the jam screw first the set screw on the shaft flat doesn't fully contact the shaft, only one small edge of the screw surface is biting. Reversing torques can easily shift the shaft to a position the flat screw no longer contacts the shaft. This lets the jam screw wriggle loose. And after a while, vibration loosens the screws until the gear is free to rotate.